Grundfos UNILIFT AP35B Installation And Operating Instructions Manual page 8

6. Unscrew the provisionally fastened guide rail
bracket, fit it on top of the guide rails and finally
fasten it firmly to the pit wall.
The guide rails must not have any axial
play as this would cause noise during
pump operation.
7. Clean out debris from the pit before lowering the
pump into the pit.
8. Fit the auto-coupling half on to the outlet of the
pump. Then slide the guide bar of this coupling
half between the guide rails and lower the pump
into the pit by means of a chain. When the pump
reaches the auto-coupling base unit, the pump will
automatically connect tightly.
9. Hang up the end of the chain on a suitable hook
at the top of the pit.
10. Adjust the length of the motor cable by coiling it
up on a relief fitting, so the cable is not damaged
during operation. Fasten the relief fitting to a
suitable bracket at the top of the pit. Make sure
that the cables are not sharply bent or pinched.
The end of the cable must not be sub-
merged, as water may penetrate
through the cable into the motor.
3.2.6 Free-standing installation
See the appendix for dimensional drawing.
For free-standing installation of the pumps, fit a 90°
elbow to the outlet. The pump can be installed with a
hose or rigid pipe and valves.
In order to facilitate service of the pump, fit a flexible
union or coupling to the outlet pipe for easy
separation.
If a hose is used, make sure that the hose does not
buckle and that the inside diameter of the hose
matches that of the outlet.
If a rigid pipe is used, the union or coupling, non-
return valve and isolating valve must be fitted in the
sequence mentioned, as seen from the pump side.
If the pump is installed in muddy conditions or on
uneven ground, we recommend that you support the
pump on bricks.
3.2.7 Adjusting the float switch cable length
For pumps supplied with a float switch, the difference
in level between start and stop can be adjusted by
changing the free cable length between the float
switch and the pump handle.
• An increased free cable length will result in fewer
starts and stops and a large difference in level.
• A reduced free cable length will result in more
frequent starts and stops and a small difference in
level.
8
The stop level must be above the pump inlet to
prevent the pump from taking in air.
3
Start and stop levels
Pos. Description
1 Stop
2 Start
3 L
The start and stop levels vary according to the cable
length.
UNILIFT AP B start and stop levels [mm]
Cable length (L)
min. 100 mm
Start Stop
500 300
Intermittent operation
During intermittent operation, the motor must always
be half submerged into the pumped liquid.
The pump is allowed to run for maximum 5 minutes
per 30 minutes without the motor being submerged in
the liquid.
Continuous operation
During continuous operation, the motor and the pump
inlet must always be completely covered by the
pumped liquid.
2
1
Cable length (L)
max. 300 mm
Start Stop
550 150